The purpose of this program is to determine the effects on progeny of immunosuppressive agents administered before or during pregnancy. One part of the study will assess the fecundity, fetal wastage and health of live-born progeny of long-term survivors of childhood cancer who received radiotherapy and chemotherapeutic agents with immunosuppressive properities. The patient resource comprises approximately 500 long-term survivors from childhood cancer. Over 50 of these patients have married and produced nearly 100 offspring. This program will attempt to investigate the progeny, monitor their health and accumulate additional patients through this resource. The second part of the program will evaluate the relationship of childhood cancer to immunosuppression by means of a detailed questionnaire to parents of patients currently undergoing treatment for malignancy at the Sidney Farber Cancer Center. The questionnaire will deal with the relationship of prior treatments with immunosuppressive agents to development of cancer in the proband and the presence of associated congenital anomalies or fetal wastage among siblings.